Tangshan People's Hospital Hepatobiliary Surgery Department
Portal vein thrombosis (PT) refers to the thrombosis occurring in the main portal vein, superior mesenteric vein, inferior mesenteric vein or splenic vein.Portal vein thrombosis can causePortal vein obstructionThe increase of portal vein pressure and intestinal congestion is an important cause of portal hypertension.Thrombotic occlusion of portal vein is often secondary to chronic liver disease and tumor disease.Simple extrahepatic portal vein occlusion is more common in adolescents and children.
The etiology of portal vein thrombosis is very complex, mainly including inflammation, tumor, coagulation dysfunction, abdominal surgery, trauma and unknown causes.
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Portal hypertension:It is mostly caused by cirrhosis and congestive splenomegaly of various causes.It is mainly due to the increase of portal vein pressure, which results in the reduction of hepatic blood flow of portal vein and its branches and the slowing of blood flow speed, resulting in eddy current, which leads to platelet accumulation and thrombosis.
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Abdominal infection:It is caused by bacteria from intestinal infectious lesions entering the portal vein system, such as neonatal omphalitis, umbilical vein sepsis, and the common adult diseases are acute appendicitis, pancreatitis, cholecystitis, small enteritis, abdominal pelvic abscess, and abdominal postoperative infection.
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Abdominal surgery and trauma:Various intraperitoneal operations can lead to thrombosis of the portal vein system, especially after splenectomy, which may be related to postoperative thrombocytosis and increased blood viscosity.After splenectomy, the portal vein blood flow decreased, and the portal vein pressure decreased, which accelerated the formation of thrombosis. In addition, the blood flow in the expanded splenic vein after surgery was slow, which contributed to the formation of splenic vein thrombosis under the hypercoagulable state.
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Blood hypercoagulability:Abdominal tumors, especially those of the colon and pancreas, are often accompanied by a hypercoagulable state of the portal vein system, which can lead to thrombosis.In recent years, it has also been found that hereditary coagulation disorder is also involved in the formation of portal vein thrombosis, including protein C, protein S and antithrombin deficiency.
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Tumor isobaric portal vein:Tumor (such as pancreatic tumor, hepatocellular carcinoma) compression, intestinal volvulus, etc. lead to portal vein system blood flow obstruction, resulting in portal vein thrombosis.
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Other reasons:It includes primary arteriosclerosis, spread of splenic vein or mesenteric vein thrombosis, some patients have a long history of taking contraceptives, and rare factors include various congestive heart failure, polycythemia, etc.
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Primary portal vein thrombosis:There is no clear cause for a few extrahepatic portal vein embolism.There may be a history of deep vein thrombosis of limbs or wandering thrombophlebitis.
clinical manifestation
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Acute type:It is rare and often occurs ① after splenectomy; ②Thrombosis at the anastomotic site of portal vena cava anastomosis; ③Continuation of splenic vein thrombosis; ④Purulent portal phlebitis; ⑤Abdominal trauma.
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Chronic type:More common, most secondary to coagulation abnormalities and portal vein blood stasis.Hepatocellular carcinoma is the most common factor in male patients with cirrhosis.
The clinical manifestations vary greatly. When the thrombosis is slowly formed, confined to the extrahepatic portal vein, and is organic, or the collateral circulation is rich, there is no or only a slight lack of specific clinical manifestations, which are often masked by the primary disease. When the acute or subacute development occurs, it shows moderate to severe abdominal pain, or sudden severe abdominal pain, splenomegaly, intractable ascites, and even intestinal necrosis in severe cases,Gastrointestinal hemorrhage and hepatic encephalopathy.
inspect
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Blood and stool tests:When intestinal necrosis complicated with bacterial infection, the white blood cell count increased, fecal occult blood was positive, creatine phosphokinase increased significantly, and even electrolyte disorder and metabolic acidosis occurred;When combined with massive gastrointestinal hemorrhage, anemia may occur, and antithrombin III factor may be reduced or deficient in patients with primary venous thrombosis.Platelets sometimes increase significantly in patients after splenectomy.
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Abdominal puncture:In case of death due to intestinal necrosis, bloody ascites can be drawn, and red blood cells can be seen by microscopic examination, with positive occult blood.
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Abdominal X-ray plain film:When combined with intestinal necrosis or paralytic intestinal obstruction, intestinal dilatation and thickening with gas-liquid level can be seen.
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Abdominal B ultrasound:Display the location, size and scope of portal vein thrombosis.The main findings were that the main portal vein, the stump of the splenic vein and the main trunk of the superior mesenteric vein were widened, and there were abnormal echoes in the veins, which were solid irregular bright spots or isoechoic spots.In case of cavernous transformation of portal vein, the main trunk and branches of portal vein disappear, and the portal vein is replaced by small and irregular tubular structures.
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Color Doppler:The diameter of the portal vein, splenic vein or superior mesenteric vein was widened and solid echo was detected. The blood flow was fine. When it was completely blocked, the blood flow signal disappeared, and the distal vein of the embolism was dilated.
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Abdominal CT:Including conventional plain scan and enhanced scan (arterial phase and venous phase), the typical CT sign of portal vein thrombosis is the presence of unenhanced low-density strip or block lesions in the portal vein cavity, and the presence of collateral veins and abnormal intestinal segments, with the correct rate of more than 90%, and the presence of splenomegaly or splenomegaly.
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Angiography:Direct or indirect portography can show the location and scope of thrombosis, and the diagnostic rate is 63%~91%.
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Magnetic resonance angiography:It can understand the patency of portal vein system, thrombosis, varicose veins, spontaneous shunt, etc.High sensitivity and specificity.
diagnosis
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Abdominal pain, abdominal abscess, portal hypertension, upper gastrointestinal bleeding, etc.
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In the process of clinical diagnosis and treatment of portal hypertension due to cirrhosis, for acute onset, unexplained abdominal pain, abdominal distention, bloody stool, unexplained upper gastrointestinal bleeding or splenomegaly, unexplained paralytic intestinal obstruction, combined with blood hypercoagulability, especially for patients with portal hypertension after disconnection surgery, the possibility of portal vein system thrombosis should be warned,However, the diagnosis should also rely on color Doppler ultrasound or CT, and those with difficulties in diagnosis should be performed with magnetic resonance angiography and portal vein angiography.
The symptoms are abdominal distention, severe abdominal pain, paroxysmal exacerbation, intestinal type or antiperistaltic wave can be seen in physical examination, and hyperechoic bowel sounds, such as air, water, or metal tones.When paralytic intestinal obstruction occurs, bowel sounds are weakened or disappear.Abdominal X-ray fluoroscopy or plain film examination showed that there were multiple ladder like fluid levels in the intestinal cavity, and a few patients had previous abdominal surgery.
The pain is mostly located in the right upper abdomen, which can radiate to the right back and scapular area. The pain is often aggravated after eating greasy food. B-ultrasound or CT can establish the diagnosis, and sometimes it can be found to coexist with gallbladder stones. The shape of the pancreas is normal, and the pancreatic duct has no dilatation.However, it must be pointed out that in a few patients with chronic cholecystitis, gallstones and chronic pancreatitis can coexist.
The symptoms of upper stomach fullness, dull pain, diarrhea and emaciation that the patient clinically shows are not unique. The patients with chronic pancreatitis also have the above symptoms, and the latter can also appear jaundice and mass, which is similar to pancreatic cancer. Therefore, it is very difficult to distinguish between the two. However, chronic pancreatitis has a long history and recurrent history,The symptoms of diarrhea and emaciation are only significant after a long course of disease.Pancreatic cancer has a short course, no history of recurrent attacks, and emaciation occurs earlier.Pancreatic calcification can be found on abdominal X-ray plain film during pancreatitis.The diagnosis can be confirmed by ultrasonography, CT or cytological examination of pancreatic masses.
treatment
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Anticoagulant treatment:As the main treatment measure, early intravenous heparin anticoagulation treatment should be performed for the newly occurred thrombus, which can lead to complete or extensive recanalization, prevent the spread of blood clots, prevent intestinal ischemia in the short term, and prevent extrahepatic portal hypertension in the long term. It is recommended to maintain oral anticoagulant treatment for at least half a year.
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Thrombolytic therapy:Thrombolytic treatment is feasible in the acute phase of the disease. The use of systemic intravenous thrombolytic drugs (urokinase) can reopen the main portal vein. In recent years, due to the improvement of the level of intervention, more local drugs are used. The early portal vein thrombosis adopts percutaneous femoral vein catheterization to the superior mesenteric artery and then catheterization,Early continuous thrombolysis with micro pump urokinase is effective for acute PT and recent PT.
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Interventional and surgical treatment:For acute portal vein thrombosis in a short period of time, portal vein incision and thrombectomy should be performed as soon as possible. For thrombosis with a long time, organized thrombosis, and poor effect of incision and thrombectomy or thrombolysis, portal azygos disconnection or portacaval shunt can be selected.
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Transjugular intrahepatic portacaval shunt:Since 1989, transjugular intrahepatic portacaval shunt, an interventional radiology technique, was introduced into clinical practice, it has become a treatment option to control portal hypertension bleeding and refractory ascites.
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Intestinal resection:Mainly for patients with mesenteric thrombosis who have intestinal necrosis and death, necrotic intestinal segment and mesentery resection are the only treatment, and continuous anticoagulation after surgery can prevent thrombosis.
complication
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The most prominent and common complication of portal vein thrombosis is esophageal and gastric varices bleeding.
